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I am a 36-year-old man who developed swelling in my left calf after flying back from Australia to New York City. The day after I returned home, I saw my physician who suspected a blood clot and sent me to a vascular specialist. A sonogram was performed, which showed that I did have a DVT in my left leg in the vein behind my knee. The doctor had me take Lovenox at home for five days and I was also placed on warfarin (Coumadin). I have been on Coumadin for the past four months. My leg is no longer bothering me and I have no pain or swelling. How long do I need to continue the warfarin?

Answer:

The usual course of treatment for a “provoked” deep vein thrombosis is three to six months. The recommendation regarding duration of treatment with warfarin varies among physicians, but I think that most would probably agree that six months of treatment is adequate, especially if you no longer have swelling or pain. What I usually recommend is a repeat sonogram to examine the condition of the veins after treatment. Clots that develop after long flights are usually what we call “provoked”, meaning that the long duration of sitting with your legs bent, particularly if seating in coach class, leads to stagnation of the blood and formation of clots. This is usually considered less concerning than an “unprovoked” DVT which means that the clot developed without any predisposing factors such as prolonged air travel, prolonged bedrest due to an illness, or recent surgery with anesthesia and bedrest. In any case, after a course of treatment, I check blood tests for signs that the patient may be “hypercoagulable” or have what we call a “thrombophilia” condition. We want to know if there is something about the patient’s blood that predisposes them to subsequent clots in the future. Typically, blood tests including protein C, protein S, factor V Leiden, antithrombin 3, cardiolipin antibodies, lupus anticoagulant, and other tests are performed. If any of these tests are positive and suggest that the patient may be at risk for developing further clots, it may be necessary to keep a patient on some form of blood thinner continuously. Another approach for such “hypercoagulable” patients is to prescribe Lovenox injections at the time of their high-risk situations. Such situations would include prolonged air travel or upcoming surgical procedures. For air travel, I typically prescribe Lovenox injections on the day of the outbound flight and the following day as well. I prescribe a repeat of that process on the inbound flight. It must be remembered that these are general guidelines. There are no rules that apply to every patient, or every situation. The treatment protocol must be individualized for each patient. This can only be done by the patient’s treating physician.